Publications

fourier transform infrared spectrum of the secondary quinone electron acceptor q(b) in photosystem ii.	fourier transform infrared difference spectra upon single reduction of the secondary quinone electron acceptor q(b) in photosystem ii (psii), without a contribution from the electron donor-side signals, were obtained for the first time using mn-depleted psii core complexes of the thermophilic cyanobacterium thermosynechococcus elongatus. the q(b)(-)/q(b) difference spectrum exhibited a strong c...o stretching band of the semiquinone anion at 1480 cm(-)(1), the frequency higher by 2 cm(-)(1) than ...	2005	16114869
[the mechanism of acetate assimilation in purple nonsulfur bacteria lacking the glyoxylate pathway: acetate assimilation in rhodobacter sphaeroides cells].	the mechanism of acetate assimilation in the purple nonsulfur bacterium rhodobacter sphaeroides, which lacks the glyoxylate pathway, is studied. it is found that the growth of this bacterium in batch and continuous cultures and the assimilation of acetate in cell suspensions are not stimulated by bicarbonate. the consumption of acetate is accompanied by the excretion of glyoxylate and pyruvate into the medium, stimulated by glyoxylate and pyruvate, and inhibited by citramalate. the respiration o ...	2005	16119843
[the mechanism of acetate assimilation in purple nonsulfur bacteria lacking the glyoxylate pathway: enzymes of the citramalate cycle in rhodobacter sphaeroides].	the mechanism of acetate assimilation by the purple nonsulfur bacterium rhodobacter sphaeroides, which lacks the glyoxylate shortcut, has been studied. in a previous work, proceeding from data on acetate assimilation by rba. sphaeroides cell suspensions, a suggestion was made regarding the operation, in this bacterium, of the citramalate cycle. this cycle was earlier found in rhodospirillum rubrum in the form of an anaplerotic reaction sequence that operates during growth on acetate instead of t ...	2005	16119844
crystal structure of 5-aminolevulinate synthase, the first enzyme of heme biosynthesis, and its link to xlsa in humans.	5-aminolevulinate synthase (alas) is the first and rate-limiting enzyme of heme biosynthesis in humans, animals, other non-plant eukaryotes, and alpha-proteobacteria. it catalyzes the synthesis of 5-aminolevulinic acid, the first common precursor of all tetrapyrroles, from glycine and succinyl-coenzyme a (scoa) in a pyridoxal 5'-phosphate (plp)-dependent manner. x-linked sideroblastic anemias (xlsas), a group of severe disorders in humans characterized by inadequate formation of heme in erythrob ...	2005	16121195
from primary photochemistry to biological function in the blue-light photoreceptors pyp and appa.	to properly respond to changes in fluency conditions, nature has developed a variety of photosensors that modulate gene expression, enzyme activity and/or motility. dedicated types have evolved, which can be classified in six families: rhodopsins, phytochromes, xanthopsins, cryptochromes, phototropins and bluf-proteins. the photochemistry of the first three families is based on cis/trans isomerization of an ethylene bond. surprisingly, the latter three all use flavin as their chromophore, but ea ...	2005	16121278
effect of lipopolysaccharides having different structures on the cardiovascular system of wistar rats.		2005	16121940
the ferredoxin-nadp(h) reductase from rhodobacter capsulatus: molecular structure and catalytic mechanism.	the photosynthetic bacterium rhodobacter capsulatus contains a ferredoxin (flavodoxin)-nadp(h) oxidoreductase (fpr) that catalyzes electron transfer between nadp(h) and ferredoxin or flavodoxin. the structure of the enzyme, determined by x-ray crystallography, contains two domains harboring the fad and nadp(h) binding sites, as is typical of the fpr structural family. the fad molecule is in a hairpin conformation in which stacking interactions can be established between the dimethylisoalloxazine ...	2005	16128574
structures of the oxidized and reduced forms of nitrite reductase from rhodobacter sphaeroides 2.4.3 at high ph: changes in the interactions of the type 2 copper.	nitrite reductase is an enzyme operating in the denitrification pathway which catalyses the conversion of nitrite (no2(-)) to gaseous nitric oxide (no). here, crystal structures of the oxidized and reduced forms of the copper-containing nitrite reductase from rhodobacter sphaeroides 2.4.3 are presented at 1.74 and 1.85 a resolution, respectively. whereas the structure of the enzyme is very similar to those of other copper-containing nitrite reductases, folding as a trimer and containing two copp ...	2005	16131751
differential regulation of periplasmic nitrate reductase gene (napkefdabc) expression between aerobiosis and anaerobiosis with nitrate in a denitrifying phototroph rhodobacter sphaeroides f. sp. denitrificans.	a denitrifying phototroph, rhodobacter sphaeroides f. sp. denitrificans, has the ability to denitrify by respiring nitrate. the periplasmic respiratory nitrate reductase (nap) catalyses the first step in denitrification and is encoded by the genes, napkefdabc. by assaying the ss-galactosidase activity of napkefd-lacz fusions in wild type and nap mutant cells grown under various growth conditions, the environmental signal for inducing nap expression was examined. under anoxic conditions with nitr ...	2005	16136296
resonance raman characterization of rhodobacter capsulatus reaction centers with lysine mutations near the accessory bacteriochlorophylls.	lysine residues have been introduced into rhodobacter capsulatus reaction centers at m-polypeptide position 201 and at l-polypeptide position 178. these positions are in the proximity of ring v of the accessory bacterochlorophylls ba and bb, respectively. resonance raman studies indicate that the introduction of a lys residue at either position m201 or l178 results in structural perturbations to the bchl cofactors. lys at l178 directly interacts with bb, most likely via a hydrogen bond. the hydr ...	2005	16143905
trapping of a long-living charge separated state of photosynthetic reaction centers in proteoliposomes of negatively charged phospholipids.	reaction centers from the purple bacterium rhodobacter sphaeroides strain r-26.1 were purified and reconstituted in proteoliposomes formed by the anionic phospholipids phosphatidylglycerol, phosphatidylserine and phosphatidylinositol and by the zwitterionic phospholipid phosphatidylcholine by size-exclusion chromatography in the dark and under illumination. we report the large stabilizing effect induced by anionic phospholipids on the protein charge separated state which results trapped in a lon ...	2005	16143907
a mechanistic principle for proton pumping by cytochrome c oxidase.	in aerobic organisms, cellular respiration involves electron transfer to oxygen through a series of membrane-bound protein complexes. the process maintains a transmembrane electrochemical proton gradient that is used, for example, in the synthesis of atp. in mitochondria and many bacteria, the last enzyme complex in the electron transfer chain is cytochrome c oxidase (cytco), which catalyses the four-electron reduction of o2 to h2o using electrons delivered by a water-soluble donor, cytochrome c ...	2005	16148937
cytochrome c oxidase as a calcium binding protein. studies on the role of a conserved aspartate in helices xi-xii cytoplasmic loop in cation binding.	the aa(3)-type cytochrome c oxidases from mitochondria and bacteria contain a cation-binding site located in subunit i near heme a. in the oxidases from paracoccus denitrificans or rhodobacter sphaeroides, the site is occupied by tightly bound calcium, whereas the mitochondrial oxidase binds reversibly calcium or sodium that compete with each other. the functional role of the site has not yet been established. d477a mutation in subunit i of p. denitrificans oxidase converts the cation-binding si ...	2005	16156652
the biosynthesis of heme o and heme a is not regulated by copper.	heme a is an obligatory cofactor in all eukaryotic and many prokaryotic cytochrome c oxidase (cco) enzymes. despite its obvious importance to cco and the electron transport pathway, essentially nothing is known concerning the regulation of heme a. because cco is the only natural target for heme a and copper is also required for cco activity, it was postulated that copper might regulate heme a homeostasis. work reported previously demonstrated that there is often a strong connection between coppe ...	2005	16156667
hydrogen independent expression of hupsl genes in thiocapsa roseopersicina bbs.	the expression of many membrane bound [nife] hydrogenases is regulated by their substrate molecule, hydrogen. the hupsl hydrogenase, encoded in the hupslcdhir operon, probably plays a role in hydrogen recycling in the phototrophic purple bacterium, thiocapsa roseopersicina bbs. rpon, coding for sigma factor 54, was shown to be important for expression, suggesting a regulated biosynthsis from the hup gene cluster. the response regulator gene, hupr, has been identified in the hup operon and expres ...	2005	16156799
biodegradation of azo dyes by genetically engineered azoreductase.	a azoreductase gene with 537 bp was obtained by pcr amplification from rhodobacter sphaeroides as1.1737. the enzyme, with a molecular weight of 18.7 kd, was efficiently expressed in escherichia coli and its biodegradation characteristics for azo dyes were investigated. furthermore, the reaction kinetics and mechanism of azo dyes catalyzed by the genetically engineered azoreductase were studied in detail. the presence of a hydrazo-intermediate was identified, which provided a convincing evidence ...	2005	16158576
construction and characterization of genetically modified synechocystis sp. pcc 6803 photosystem ii core complexes containing carotenoids with shorter pi-conjugation than beta-carotene.	beta-carotene has been identified as an intermediate in a secondary electron transfer pathway that oxidizes chl(z) and cytochrome b(559) in photosystem ii (ps ii) when normal tyrosine oxidation is blocked. to test the redox function of carotenoids in this pathway, we replaced the zeta-carotene desaturase gene (zds) or both the zds and phytoene desaturase (pds) genes of synechocystis sp. pcc 6803 with the phytoene desaturase gene (crti) of rhodobacter capsulatus, producing carotenoids with shorte ...	2005	16159754
thermodynamics of light-induced and thermal degradation of bacteriochlorins in reaction center protein of photosynthetic bacteria.	the rate constants of thermal (irreversible) damage of bacteriochlorin pigments (bacteriochlorophyll monomer [b], bacteriochlorophyll dimer [p] and bacteriopheophytine [h]) in reaction center [rc] protein from the photosynthetic bacterium rhodobacter sphaeroides were studied in the dark and during intense (400 mw x cm(-2)) laser light excitation (wavelengths 488 and 515 nm) under deoxygenated conditions. while the kinetics of degradation of p and b were monoexponential, the decay kinetics of h w ...	2005	16164369
g204d, a mutation that blocks the proton-conducting d-channel of the aa3-type cytochrome c oxidase from rhodobacter sphaeroides.	cytochrome c oxidase uses the free energy of oxygen reduction to establish a transmembrane proton gradient. the proton-conducting d-channel in this enzyme is the major input pathway for protons which go to the binuclear center for water formation ("chemical protons") and likely the only input pathway for protons that get translocated across the lipid membrane ("pumped protons"). the d-channel starts at an acidic residue near the protein surface (d132, rhodobacter sphaeroides numbering) and leads ...	2005	16171391
band structure and local dynamics of excitons in bacterial light-harvesting complexes revealed by spectrally selective spectroscopy.	hole-burned absorption and line-narrowed fluorescence spectra are studied at 5 k in wild type and mutant lh1 and lh2 antenna preparations from the photosynthetic purple bacterium rhodobacter sphaeroides. evidence was found in all samples, even in intact membranes, of the presence of a broad distribution of bacteriochlorophyll species that are unable to communicate energy between each other and to the exciton states of functional antenna complexes. the distribution maximum of these localized spec ...	2005	16172924
temperature broadening of lh2 absorption in glycerol solution.	in order to determine the relationship between the pigment-protein and the pigment-pigment interactions, the measurements of absorption spectra of the peripheral light-harvesting complex lh2 from the purple bacteria rhodobacter sphaeroides solvated in glycerol/buffer solution were carried out in a wide temperature range, from 4 to 250 k. the sdfs used for simulating the temperature dependence of b800 and b850 bands were determined in a parametric form. to fit experimental spectra the overall exc ...	2005	16172925
characterization of a highly purified, fully active, crystallizable rc-lh1-pufx core complex from rhodobacter sphaeroides.	photosynthetic complexes in bacteria absorb light and undergo photochemistry with high quantum efficiency. we describe the isolation of a highly purified, active, reaction center-light-harvesting 1-pufx complex (rc-lh1-pufx core complex) from a strain of the photosynthetic bacterium, rhodobacter sphaeroides, which lacks the light-harvesting 2 (lh2) and contains a 6 histidine tag on the h subunit of the rc. the complex was solubilized with diheptanoyl-sn-glycero-3-phosphocholine (dhpc), and purif ...	2005	16172926
on the role of basic residues in adapting the reaction centre-lh1 complex for growth at elevated temperatures in purple bacteria.	the purple photosynthetic bacterium thermochromatium tepidum is a moderate thermophile, with a growth optimum of 48-50 degrees c. the x-ray crystal structure of the reaction centre from this organism has been determined, and compared with that from mesophilic bacteria such as blastochloris viridis and rhodobacter sphaeroides (nogi t et al. (2000) proc natl acad sci usa 97: 13561-13566). structural features that could contribute to the enhanced thermal stability of the thermochromatium tepidum re ...	2005	16172928
in situ electrooxidation of photobiological hydrogen in a photobioelectrochemical fuel cell based on rhodobacter sphaeroides.	in this paper, we present a photobiological fuel cell that utilizes the metabolic activity of living cells of rhodobacter sphaeroides for the generation of electricity based on the in situ oxidation of photobiological hydrogen. organic acids and alcohols contained in synthetic media as well as in fermented media of escherichia coli k 12 served as the proton donor source for the photobiological hydrogen production by r. sphaeroides. we demonstrate thatthe photobiological hydrogen is efficiently o ...	2005	16173600
replacement or exclusion of the b-branch bacteriopheophytin in the purple bacterial reaction centre: the h(b) cofactor is not required for assembly or core function of the rhodobacter sphaeroides complex.	all of the membrane-embedded cofactors of the purple bacterial reaction centre have well-defined functional or structural roles, with the exception of the bacteriopheophytin (h(b)) located approximately half-way across the membrane on the so-called inactive- or b-branch of cofactors. sequence alignments indicate that this bacteriochlorin cofactor is a conserved feature of purple bacterial reaction centres, and a pheophytin is also found at this position in the photosystem-ii reaction centre. pos ...	2005	16181607
proton release due to manganese binding and oxidation in modified bacterial reaction centers.	the ph dependence of binding and oxidation of mn2+ in highly oxidizing reaction centers with designed metal-binding sites was characterized by light-minus-dark optical difference spectroscopy and direct measurements of proton uptake/release. these mutants bind a mn2+ ion that can efficiently transfer an electron to the oxidized bacteriochlorophyll dimer, as described earlier [thielges et al. (2005) biochemistry 44, 7389-7394]. the dissociation constant, kd, significantly increased with decreasin ...	2005	16201752
tryptophan at position 104 is involved in transforming light signal into changes of beta-sheet structure for the signaling state in the bluf domain of appa.	appa is a member of an fad-based new class blue-light sensory protein known as sensor of blue light using fad (bluf) protein. the spectroscopic properties of an appa bluf domain (appa126), in which the tryptophan residue at position 104 had been replaced with alanine (w104a), were characterized. the w104a mutant appa126 showed a nearly normal absorption red shift in the fad uv-visible absorption upon illumination; however, the light state relaxed to the dark state at a rate approximately 150 tim ...	2005	16204305
identification of bacteria potentially responsible for oxic and anoxic sulfide oxidation in biofilters of a recirculating mariculture system.	bacteria presumably involved in oxygen- or nitrate-dependent sulfide oxidation in the biofilters of a recirculating marine aquaculture system were identified using a new application of reverse transcription-pcr denaturing gradient gel electrophoresis (dgge) analysis termed differential-transcription (dt)-dgge. biofilter samples were incubated in various concentrations of sulfide or thiosulfate (0 to 5 mm) with either oxygen or nitrate as the sole electron acceptor. before and after short-term in ...	2005	16204531
combining microarray and genomic data to predict dna binding motifs.	the ability to detect regulatory elements within genome sequences is important in understanding how gene expression is controlled in biological systems. in this work, microarray data analysis is combined with genome sequence analysis to predict dna sequences in the photosynthetic bacterium rhodobacter sphaeroides that bind the regulators prra, ppsr and fnrl. these predictions were made by using hierarchical clustering to detect genes that share similar expression patterns. the dna sequences upst ...	2005	16207904
incorporation of selenomethionine into induced intracytoplasmic membrane proteins of rhodobacter species.	efficient multiple- or single-wavelength anomalous dispersion (mad/sad) techniques that use tunable x-ray sources at third-generation synchrotrons exploit the anomalous scattering of certain heavy atoms for determination of experimental phases. development of methods for the in vivo substitution of methionine by selenomethionine (semet) has revolutionized the process for determination of structures of soluble proteins in recent years. herein, we report methods for biosynthetic incorporation of s ...	2005	16211505
[high-order derivative spectroscopy of infrared absorption spectra of the reaction centers from rhodobacter sphaeroides].	the infrared absorption spectra of reduced and chemically oxidized reaction center preparations from the purple bacterium rhodobacter sphaeroides were investigated by means of high-order derivative spectroscopy. the model gaussian band with a maximum at 810 nm and a half-band of 15 nm found in the absorption spectrum of the reduced reaction center preparation is eliminated after the oxidation of photoactive bacteriochlorophyll dimer (p). this band was related to the absorption of the p(+)y excit ...	2005	16212058
the pufx protein of rhodobacter capsulatus affects the properties of bacteriochlorophyll a and carotenoid pigments of light-harvesting complex 1.	a pufx gene deletion in the purple bacterium rhodobacter capsulatus causes a severe photosynthetic defect and increases core light-harvesting complex (lh1) protein and bacteriochlorophyll a (bchl) levels. it was suggested that pufx interrupts the lh1 alpha/beta ring around the reaction centre, allowing quinone/quinol exchange. however, naturally pufx(-) purple bacteria grow photosynthetically with an uninterrupted lh1. we discovered that substitutions of the rhodobacter-specific lh1 alpha seryl- ...	2005	16212932
magnetic field dependence of photo-cidnp mas nmr on photosynthetic reaction centers of rhodobacter sphaeroides wt.	photochemically induced dynamic nuclear polarization (photo-cidnp) is observed in frozen and quinone depleted photosynthetic reaction centers of the purple bacteria rhodobacter sphaeroides wild type (wt) by (13)c solid-state nmr at three different magnetic fields. all light-induced signals appear to be emissive at all three fields. at 4.7 t (200 mhz proton frequency), the strongest enhancement of nmr signals is observed, which is more than 10 000 above the boltzmann polarization. at higher field ...	2005	16218623
microbial dimethylsulfoxide and trimethylamine-n-oxide respiration.	over the last two decades, the biochemistry and genetics of dimethylsulfoxide (dmso) and trimethylamine-n-oxide (tmao) respiration has been characterised, particularly in escherichia coli marine bacteria of the genus shewanella and the purple phototrophic bacteria, rhodobacter sphaeroides and r. capsulatus. all of the enzymes (or catalytic subunits) involved the final step in dmso and tmao respiration contain a pterin molybdenum cofactor and are members of the dmso reductase family of molybdoenz ...	2005	16221580
b-branch electron transfer in reaction centers of rhodobacter sphaeroides assessed with site-directed mutagenesis.	mutants of rhodobacter (rba.) sphaeroides are described which were designed to study electron transfer along the so-called b-branch of reaction center (rc) cofactors. combining the mutation l(m214)h, which results in the incorporation of a bacteriochlorophyll, beta, for h(a) [kirmaier et al. (1991) science 251: 922-927] with two mutations, g(m203)d and y(m210)w, near b(a), we have created a double and a triple mutant with long lifetimes of the excited state p(*) of the primary donor p, viz. 80 a ...	2002	16228134
accumulation of unusual carotenoids in the spheroidene pathway, demethylspheroidene and demethylspheroidenone, in an alkaliphilic purple nonsulfur bacterium rhodobaca bogoriensis.	carotenoids extracted from cells of a novel alkaliphilic purple nonsulfur bacterium rhodobaca bogoriensis strain lbb1 included unusual carotenoids in the spheroidene pathway; demethylspheroidene, demethylspheroidenone, neurosporene and spheroidenone. spheroidene was present in only small amounts, and the demethyl-carotenoids demethylspheroidene and demethylspheroidenone predominated in phototrophic cultures. furthermore, the keto-carotenoids spheroidenone and demethylspheroidenone constituted ne ...	2001	16228308
photoinhibition of carotenoidless reaction centers from rhodobacter sphaeroides by visible light. effects on protein structure and electron transport.	inhibition of electron transport and damage to the protein subunits by visible light has been studied in isolated reaction centers of the non-sulfur purple bacterium rhodobacter sphaeroides. illumination by 1100 muem(-2) s(-1) light induced only a slight effect in wild type, carotenoid containing 2.4.1. reaction centers. in contrast, illumination of reaction centers isolated from the carotenoidless r26 strain resulted in the inhibition of charge separation as detected by the loss of the initial ...	2001	16228351
the home stretch, a first analysis of the nearly completed genome of rhodobacter sphaeroides 2.4.1.	rhodobacter sphaeroides 2.4.1 is an alpha-3 purple nonsulfur eubacterium with an extensive metabolic repertoire. under anaerobic conditions, it is able to grow by photosynthesis, respiration and fermentation. photosynthesis may be photoheterotrophic using organic compounds as both a carbon and a reducing source, or photoautotrophic using carbon dioxide as the sole carbon source and hydrogen as the source of reducing power. in addition, r. sphaeroides can grow both chemoheterotrophically and chem ...	2001	16228360
the rhodobacter capsulatus genome.	the genome of rhodobacter capsulatus has been completely sequenced. it consists of a single chromosome containing 3.5 mb and a circular plasmid of 134 kb. this effort, started in 1992, began with a fine-structure restriction map of an overlapping set of cosmids that covered the genome. cosmid sequencing led to a gapped genome that was filled by primer walking on the chromosome and by using lambda clones. methods had to be developed to handle strong stops in the high gc (68%) inserts. annotation ...	2001	16228361
orf90, a gene required for photoreactivation in rhodobacter capsulatus sb1003 encodes a cyclobutane pyrimidine dimer photolyase.	based on deduced amino-acid sequence similarities to class-i photolyases, the open reading frame orf90 was identified from the genome sequence of rhodobacter capsulatus sb1003. photoreactivation activity is not detectable in an orf90 deletion mutant of r. capsulatus sb1003. the phenotype of r. capsulatus wild-type cells was restored by plasmid borne orf90 of r. capsulatus deltaorf90. furthermore, we detected an orf90-related cpd-specific photoreactivation activity in r. capsulatus cell extracts. ...	2004	16228391
phylogenetic distribution of unusual triheme to tetraheme cytochrome subunit in the reaction center complex of purple photosynthetic bacteria.	to understand the evolutionary relationship between triheme and tetraheme cytochrome subunits in the reaction center complex, genes located downstream of that coding for the m subunit of the reaction center complex (pufm) were amplified by pcr and analyzed in six established and two unidentified species of the genus rhodovulum and five species of the genus rhodobacter. all the rhodovulum species tested had the pufc gene coding for the reaction-center-bound cytochrome subunit, while all the rhodo ...	2004	16228402
effects of precise deletions in rhodobacter sphaeroides reaction center genes on steady-state levels of reaction center proteins: a revised model for reaction center assembly.	possible interactions between photosynthetic reaction center (rc) proteins that protect these membrane proteins from proteolytic digestion in rc complex assembly were evaluated by use of translationally in-frame (nonpolar) rc gene-specific deletions. the rc h, rc m and rc l proteins were produced from plasmids, either alone or in concert with one or both of the others, in a strain of rhodobacter sphaeroides that contained chromosomal deletions of all three rc genes. the steady-state amounts of t ...	2004	16228404
structure and dynamics of photosynthetic membrane-bound proteins in rhodobacter sphaeroides, studied with solid-state nmr spectroscopy.	the photosynthetic purple bacteria such as rb. sphaeroides possesses an intracytoplasmic membrane (icm) and a variety of pigment-binding membrane proteins located in the icm, acting as photoreceptor. such photosynthetic apparatus is concentrated in the icm. it is composed of three multimeric membrane-bound proteins; light-harvesting complexes (lh 1, lh 2), a reaction center (rc) and a cytochrome b/c1 complex. we have purified these membranes, which are called chromatophores, and characterized th ...	2000	16228436
cloning, sequencing and analysis of the pucc genes from rubrivivax gelatinosus strain 151 and rhodopseudomonas acidophila strain 10050.	the pucc genes of rubrivivax gelatinosus strain 151 and rhodopseudomonas acidophila strain 10050 have been identified, cloned and sequenced. in rubrivivax gelatinosus the arrangement of the pucc gene with regard to the pucba genes was shown to differ from that found in other species of photosynthetic bacteria. the rhodopseudomonas acidophila pucc was found downstream of four new pucba gene pairs, bringing the sequenced pucba pairs to a total of eight in this strain. the predicted pucc protein se ...	2000	16228472
theoretical studies on the mechanism of primary electron transfer in the photosynthetic reaction center of rhodobacter sphaeroides.	the mechanism of the primary electron transfer (et) process in the photosynthetic reaction center (prc) of rhodobacter sphaeroides has been studied with quantum chemistry method of ab initio density functional theory (dft) (b3lyp/6-31g) based on the optimized x-ray crystallographic structure. the calculation was carried out on different structural levels. the electronic structure of pigment molecules was first studied, and then the influence of the neighboring protein was taken into account at t ...	2002	16228542
the structure of the heterodimer reaction center from rhodobacter sphaeroides at 2.55 å resolution.	crystals have been obtained of reaction centers of the heterodimer mutant that has significantly different properties than wild type due to the primary donor being formed from both a bacteriochlorophyll and bacteriopheophytin rather than two bacteriochlorophylls as found for wild type. the crystals belong to the trigonal space group p3(1)21 and the structure has been refined to a resolution limit of 2.55 a with an r factor of 19.0%. the electron density maps confirm that a primary donor does ind ...	2002	16228547
analysis of the upstream sequences of the rhodobacter sphaeroides 2.4.1 hema gene: in vivo evidence for the presence of two promoters that are both regulated by fnrl.	the presumed dna target for the rhodobacter sphaeroides 2.4.1 fnrl regulatory protein is the fnr consensus sequence, ttgat-n(4)-atcaa, based on (1) similarities between the helix-turn-helix motifs of fnrl and the escherichia coli homologue, fnr, and (2) the established fnrl dependence for anaerobic induction of six gene clusters all having upstream fnr consensus-like sequences. we are interested in understanding the regulation of one among these; namely, the hema gene, which codes for one of two ...	2002	16228552
membrane-anchored cytochrome c as an electron carrier in photosynthesis and respiration: past, present and future of an unexpected discovery.	in the mid 1980s, it was observed that photosynthesis could still occur in the absence of the diffusible electron carrier cytochrome c (2) in the purple non-sulfur facultative phototrophic bacterium rhodobacter capsulatus. this serendipic finding led to the discovery of a novel class of membrane-anchored electron carrier cytochromes and their associated electron transfer pathways. studies of cytochrome c (y) of r. capsulatus (and its homologues in other species) have modified the previous dogma ...	2003	16228572
light-induced behavioral responses (;phototaxis') in prokaryotes.	light-induced sensory responses are among the oldest scientific observations on bacterial behavior. various types of response have been characterized physiologically in detail. however, the molecular basis of this type of response is only slowly emerging. in many of these systems photosynthetic pigments absorb the light. this then generates a signal via electron transport, feeding into a canonical chemotaxis signal transduction pathway. nevertheless, several examples have been identified in whic ...	2003	16228574
interaction of bacteriochlorophyll with the lh1 and pufx polypeptides of photosynthetic bacteria: use of chemically synthesized analogs and covalently attached fluorescent probes.	the protein components of the reaction center (rc) and core light-harvesting (lh 1) complexes of photosynthetic bacteria have evolved to specifically, but non-covalently, bind bacteriochlorophyll (bchl). the contribution to binding of specific structural elements in the protein and bchl may be determined for the lh 1 complex because its subunit can be studied by reconstitution under equilibrium conditions. important to the determination and utilization of such information is the characterization ...	2003	16228601
characterization of a semi-stable, charge-separated state in reaction centers from rhodobacter sphaeroides.	in reaction centers from rhodobacter sphaeroides, subjected to continuous illumination in the presence of an inhibitor of the q(a) to q(b) electron transfer, the oxidation of p870 consisted of several kinetic phases with a fast initial reaction followed by very slow accumulation of p870(+) with a halftime of several minutes. when the light was turned off, a phase of fast charge recombination was followed by an equally slow reduction of p870(+). in reaction centers depleted of q(b), where forward ...	2003	16228603
triplet excitation transfer between carotenoids in the lh2 complex from photosynthetic bacterium rhodopseudomonas palustris.	we have studied, by means of sub-microsecond time-resolved absorption spectroscopy, the triplet-excited state dynamics of carotenoids (cars) in the intermediate-light adapted lh2 complex (ml-lh2) from rhodopseudomonas palustris containing cars with different numbers of conjugated double bonds. following pulsed photo-excitation at 590 nm at room temperature, rapid spectral equilibration was observed either as a red shift of the isosbestic wavelength on a time scale of 0.6-1.0 mus, or as a fast de ...	2004	16228615
treatment of aquarium water by denitrifying photosynthetic bacteria using immobilized polyvinyl alcohol beads.	during the purification of an aquarium for carp breeding, a relatively high level of chemical oxygen demand (cod) was removed by filtration systems packed with both alginate- and polyvinyl alcohol (pva)-immobilized gel beads of rhodobacter sphaeroides s. low nitrate accumulation was observed in the alginate gel beads packed system due to denitrification, but high levels of nitrate and nitrite accumulation were observed in the pva gel beads packed system. this phenomenon was caused by the inhibit ...	1999	16232449
enhanced hydrogen production by a mutant of rhodobacter sphaeroides having an altered light-harvesting system.	a stable mutant of the photosynthetic bacterium rhodobacter sphaeroides with an altered light-harvesting (lh) system (p3 mutant) was obtained by uv irradiation and characterized. the mutant exhibited a 2.7-fold decrease in the core antennal (lh1) content and 1.6-fold increase in peripheral antennal (lh2) content compared to the wild-type strain. the h2 evolution rates in the p3 mutant under 800- and 850-nm light, corresponding to the absorption maxima of lh2, were 1.5 times higher than in the wi ...	1999	16232528
rhodobacter sphaeroides mutants which accumulate 5-aminolevulinic acid under aerobic and dark conditions.	the photosynthetic bacterium rhodobacter sphaeroides accumulates 5-aminolevulinic acid (ala), which is a precursor in tetrapyrrole biosynthesis, under light illumination and upon addition of levulinic acid as an inhibitor of ala dehydratase. to generate an industrial strain which produces ala in the absence of light, we sequentially mutated r. sphaeroides cr-286 using n-methyl-n'-nitro-n-nitrosoguanidine (ntg). the mutant strains were screened by cultivating in the absence of light and assayed f ...	1999	16232557
photobiological hydrogen production.	the principles and recent progress in the research and development of photobiological hydrogen production are reviewed. cyanobacteria produce hydrogen gas using nitrogenase and/or hydrogenase. hydrogen production mediated by native hydrogenases in cyanobacteria occurs under in the dark under anaerobic conditions by degradation of intracellular glycogen. in vitro and in vivo coupling of the cyanobacterial photosynthetic system with a clostridial hydrogenase via cyanobacterial ferredoxin was demon ...	1999	16232564
sulfide oxidation by gene expressions of sulfide-quinone oxidoreductase and ubiquinone-8 biosynthase in escherichia coli.	sulfides (s2),sh-) such as hydrogen sulfide belong to a class of sulfur compounds with unpleasant odors. in order to confer sulfide-oxidizing ability on the intestine-inhabiting bacteria, the sulfide-quinone oxidoreductase gene (sqr) in rhodobacter capsulatus dsm-155 and genes for quinone biosynthesis (ubic, ubia and ispb) in escherichia coli xl1 blue-mrf' were transduced into e. coli bl21(de3). plasmids pt7-7 and pstv were used as vectors of sqr, and ubica and ispb, respectively. the recombinan ...	1999	16232606
removal of phosphorus from oyster farm mud sediment using a photosynthetic bacterium, rhodobacter sphaeroides il106.	removal of phosphorous compounds from the mud sediment of an oyster farm was carried out by a series of bio-processes under anaerobic conditions. anaerobic acidogenic fermentation of a mud sediment suspension (200 g wet wt/l artificial sea water) was initially carried out. with the addition of vitamins such as thiamine, nicotinic acid and biotin, acidogenic fermentation was enhanced to yield acetic acid of approximately 2 g/l. furthermore, approximately 20 mg/l of po4(3-) (10% of total phosphoru ...	1999	16232636
entrapment of rhodobacter sphaeroides rv in cationic polymer/agar gels for hydrogen production in the presence of nh4+.	cationic polyelectrolytes (chitosan, poly-l-lysine (pll), polyethyleneimine (pei) and trimethylammonium glycol chitosan iodide (tgci)) were used to entrap anoxygenic phototrophic bacteria in order to prevent the inhibitory effect of nh4+ on hydrogen production. when combined with agar gel, chitosan and pll demonstrated no obvious repressive effect on hydrogen production by rhodobacter sphaeroides under light-anaerobic conditions with lactate and glutamate as the carbon and nitrogen sources, resp ...	1999	16232653
simulation of the daily sunlight illumination pattern for bacterial photo-hydrogen production.	methods of illumination to simulate the daily sunlight irradiation pattern were studied in relation to photohydrogen production using the photosynthetic bacterium rhodobacter sphaeroides rv. three illumination patterns were compared, in which the light intensity was changed in 1, 3, or 6 steps. as a control, outdoor experiments were also carried out over a 3-d period in tsukuba, august 1996. outdoors, hydrogen production by rba. sphaeroides rv was dependent on the sunlight intensity: the total v ...	1999	16232680
microbial hydrogen production from sweet potato starch residue.	clostridium butyricum could produce hydrogen from a sweet potato starch residue upon supplementation of nitrogen sources. a repeated batch culture using a mixed culture of c. butyricum and enterobacter aerogenes produced hydrogen with a yield of 2.4 mol h2/mol glucose under a controlled culture ph of 5.25 in a medium consisting of the sweet potato starch residue and 0.1% polypepton without addition of any reducing agents. rhodobacter sp. m-19 produced hydrogen from the supernatant of the culture ...	2001	16232947
salt-stress-responsive membrane proteins in rhodobacter sphaeroides f. sp. denitrificans il 106.	the salt-mediated-stress response in rhodobacter sphaeroides f. sp. denitrificans il 106 was investigated by culturing cells in the presence and in the absence of nacl in growth media. fractionation of cells followed by sds-page and 2d-page revealed an increase in the levels of membrane proteins of 39 and 50 kda and a decrease in the level of a membrane protein of 52 kda with increasing levels of external nacl. the proteins were isolated and sequenced. the polypeptide of 50 kda in the inner memb ...	2001	16232981
efficient removal of sulfide following integration of multiple copies of the sulfide-quinone oxidoreductase gene (sqr) into the escherichia coli chromosome.	for the oxidation and removal of hydrogen sulfide, which causes an offensive odor from the contents of animal intestines, recombinant strains of escherichia coli were constructed. the sulfide-quinone oxidoreductase gene (sqr) from rhodobacter capsulatus was integrated in low copy numbers into the chromosome of escherichia coli w3110. multiple copies of sqr on plasmids were also delivered into the cytoplasm of the same strain. the sqr genes were homologously transducted onto the chromosomal lacz ...	2001	16233028
genetic manipulation system in propionibacteria.	members of the genus propionibacterium are widely used in the production of vitamin b12, tetrapyrrole compounds, and propionic acid as well as in probiotic and cheese industries. shuttle vectors were developed in propionibacteria using replicons from endogenous plasmids in propionibacterium and escherichia coli and an appropriate selection marker. the efficient transformation was achieved using the shuttle vector prepared from propionibacterium freudenreichii to overcome the high restriction mod ...	2002	16233156
enhancement of hydrogen production by a photosynthetic bacterium mutant with reduced pigment.	a novel mutant mtp4 was created from the wild-type strain rhodobacter sphaeroides rv by uv irradiation for the enhancement of hydrogen production. the amount of light absorbed by mtp4 was lower than that by the wild-type strain at any wavelengths ranging from 350 to 1000 nm. this nature enables the illumination of cells in the deeper parts of a reactor. the contents of bacteriochlorophylls and carotenoids of the chromatophores prepared from mtp4 under the conditions for hydrogen production were ...	2002	16233179
biosorption of cadmium ions using a photosynthetic bacterium, rhodobacter sphaeroides s and a marine photosynthetic bacterium, rhodovulum sp. and their biosorption kinetics.	we examined the biosorption characteristics of cadmium ions onto a photosynthetic bacterium, rhodobacter sphaeroides s and a marine photosynthetic bacterium rhodovulum sp. ps88 in a batch culture system. both photosynthetic bacteria are capable of cadmium removal with 30 g/l sodium chloride and divalent cations (mg2+ and ca2+) in the culture medium. in particular, the strain ps88 shows a high removal ratio and high specific removal rate of cadmium ions from the culture medium under aerobic-dark ...	2003	16233422
stimulation of porphyrin production by application of an external magnetic field to a photosynthetic bacterium, rhodobacter sphaeroides.	the effects of an external magnetic field on the production of porphyrin were investigated using rhodobacter sphaeroides if012203 under anaerobic-light conditions. upon application of a 0.13-0.3-t magnetic field, the growth was slightly suppressed and porphyrin extracellular production was activated at both the n and s poles, particularly at the n pole up to about 5.3 times that in the control experiment (6.7 mg/1) (without magnetic filed application). the maximum production was 35.8 mg/1 at the ...	2003	16233427
production of vitamin b12 in genetically engineered propionibacterium freudenreichii.	since the chemical synthesis of vitamin b12 requires more than 70 steps, the production of vitamin b12 has been achieved by microorganism fermentation with additional brief chemical modifications. in an effort to increase the productivity of vitamin b12, we tried to express 10 genes belonging to the hem, cob and cbi gene families involved in the synthesis of vitamin b12 in propionibacterium freudenreichii, which is a known producer of vitamin b12. in a recombinant p. freudenreichii clone that ha ...	2004	16233685
the nature and function of the catalytic centres of the dmso reductases.	density functional theory calculations have been performed to probe aspects of the function of the reaction centres of the dmso reductase enzymes, in respect of catalysis of oxygen atom transfer (oat). the first comparison between mo and w at the active site of these enzymes has been accomplished by a consideration of the reaction profile for oat from dmso to [moiv(ome)(s2c2h2)2]1- versus that for the corresponding reaction with [wiv(ome)(s2c2h2)2]1-. both reaction profiles involve two transitio ...	2005	16234940
transcriptome and physiological responses to hydrogen peroxide of the facultatively phototrophic bacterium rhodobacter sphaeroides.	the transcriptome responses to hydrogen peroxide, h2o2, of the facultatively phototrophic bacterium rhodobacter sphaeroides grown under semiaerobic conditions were investigated. at 7 min after the addition of 1 mm h2o2, the expression of approximately 9% of all genes (total, 394) was changed reliably by at least twofold. at 30 min, the number of genes (total, 88) and the magnitude of expression changes were much lower, indicating rapid recovery from stress. two types of responses were observed: ...	2005	16237007
requirements for chemotaxis protein localization in rhodobacter sphaeroides.	many proteins have recently been shown to localize to different regions of the bacterial cell. this is most striking in the case of the escherichia coli chemotaxis pathway in which the components localize at the cell poles. rhodobacter sphaeroides has a more complex chemotaxis system with two complete pathways, each localizing to different positions, one pathway at the pole and one at a discrete cluster within the cytoplasm of the bacterium. using genomic replacement of the wild-type chemotaxis ...	2005	16238635
light-dependent regulation of photosynthesis genes in rhodobacter sphaeroides 2.4.1 is coordinately controlled by photosynthetic electron transport via the prrba two-component system and the photoreceptor appa.	formation of the photosynthetic apparatus in rhodobacter is regulated by oxygen tension and light intensity. here we show that in anaerobically grown rhodobacter cells a light-dependent increase in expression of the puc and puf operons encoding structural proteins of the photosynthetic complexes requires an active photosynthetic electron transport. the redox-sensitive crtj/ppsr repressor of photosynthesis genes, which was suggested to mediate electron transport-dependent signals, is not involved ...	2005	16238636
analysis of the kinetics of the membrane potential generated by cytochrome c oxidase upon single electron injection.	in a recent work from this group (popovic, d. m.; stuchebrukhov a. a. febs lett. 2004, 566, 126), a model of proton pumping by cytochrome c oxidase (cco) was proposed. the key element of the model is his291 (bovine notation), a histidine ligand to enzyme's cub redox center, which plays the role of the pump element. the model assumes that upon electron transfer between heme a and the binuclear catalytic center of the enzyme, two sequential proton transfers occur: first, a proton from glu242 is tr ...	2005	16242114
photosynthesis genes and their expression in rhodobacter sphaeroides 2.4.1: a tribute to my students and associates.	this minireview traces the photosynthesis genes, their structure, function and expression in rhodobacter sphaeroides 2.4.1, as applied to our understanding of the inducible photosynthetic intracytoplasmic membrane system or icm. this focus has represented the research interests of this laboratory from the late 1960s to the present. this opportunity has been used to highlight the contributions of students and postdoctorals to this research effort. the work described here took place in a much grea ...	2002	16245109
low-temperature interquinone electron transfer in photosynthetic reaction centers from rhodobacter sphaeroides and blastochloris viridis: characterization of q(b)- states by high-frequency electron paramagnetic resonance (epr) and electron-nuclear double resonance (endor).	high-frequency electron paramagnetic resonance (hf epr) techniques have been employed to look for localized light-induced conformational changes in the protein environments around the reduced secondary quinone acceptor (q(b)(-)) in rhodobacter sphaeroides and blastochloris viridis rcs. the q(a)(-) and q(b)(-) radical species in fe-removed/zn-replaced protonated rcs substituted with deuterated quinones are distinguishable with pulsed d-band (130 ghz) epr and provide native probes of both the low- ...	2005	16245929
induced conformational changes upon cd2+ binding at photosynthetic reaction centers.	cd(2+) binding at the bacterial photosynthetic reaction center (brc) from rhodobacter sphaeroides is known to inhibit proton transfer (pt) from bulk solvent to the secondary quinone q(b). to elucidate this mechanism, we calculated the pk(a) for residues along the water channels connecting q(b) with the stromal side based on the crystal structures of wt-brc and cd(2+)-bound brc. upon cd(2+) binding, we observed the release of two protons from his-h126/128 at the cd(2+) binding site and significan ...	2005	16254054
an isotope-edited ftir investigation of the role of ser-l223 in binding quinone (qb) and semiquinone (qb-) in the reaction center from rhodobacter sphaeroides.	in the photosynthetic reaction center (rc) from the purple bacterium rhodobacter sphaeroides, proton-coupled electron-transfer reactions occur at the secondary quinone (q(b)) site. several nearby residues are important for both binding and redox chemistry involved in the light-induced conversion from q(b) to quinol q(b)h(2). ser-l223 is one of the functionally important residues located near q(b). to obtain information on the interaction between ser-l223 and q(b) and q(b)(-), isotope-edited q(b) ...	2005	16262252
the flagellar hierarchy of rhodobacter sphaeroides is controlled by the concerted action of two enhancer-binding proteins.	the expression of the bacterial flagellar genes follows a hierarchical pattern. in rhodobacter sphaeroides the flagellar genes encoding the hook and basal body proteins are expressed from sigma54-dependent promoters. this type of promoters is always regulated by transcriptional activators that belong to the family of the enhancer-binding proteins (ebps). we searched for possible ebps in the genome of r. sphaeroides and mutagenized two open reading frames (orfs) (fleq and flet), which are in the ...	2005	16262784
investigation of oscillatoria spongeliae-dominated bacterial communities in four dictyoceratid sponges.	certain species of marine sponges in the order dictyoceratida harbor large populations of the cyanobacterial symbiont oscillatoria spongeliae in the mesohyl (interior) of the sponge. we show that in four of these sponge species (lamellodysidea herbacea, lamellodysidea chlorea, lendenfeldia chondrodes, and phyllospongia papyracea) from palau there is a consistent community of alpha-proteobacteria in addition to o. spongeliae that fall within the rhodobacter group based on 16s rrna gene analysis. ...	2005	16269779
spectroscopic and kinetic characterization of the light-dependent enzyme protochlorophyllide oxidoreductase (por) using monovinyl and divinyl substrates.	the enzyme por [pchlide (protochlorophyllide) oxidoreductase] catalyses the reduction of pchlide to chlorophyllide, which is a key step in the chlorophyll biosynthesis pathway. this light-dependent reaction has previously been studied in great detail but recent reports suggest that a mixture of mv (monovinyl) and dv (divinyl) pchlides may have influenced some of these properties of the reaction. low-temperature absorbance and fluorescence spectroscopy have revealed several spectral differences b ...	2006	16274361
discovery of complex mixtures of novel long-chain quorum sensing signals in free-living and host-associated marine alphaproteobacteria.	more than 100 bacterial isolates from various marine habitats were screened for ahl production by using gfp reporter constructs based on the lasr system of pseudomonas aeruginosa and the luxr system of vibrio fischeri. of the 67 alphaproteobacteria tested, most of which belonged into the so-called roseobacter clade, 39 induced fluorescence in either one or both sensor strains up to 103-fold compared to controls. acylated homoserine lactones were identified by gc-ms analysis and shown to have cha ...	2005	16283687
adsorption of heavy metal ions to floc-type biosorbents.	adsorption of cadmium and lead ions to floc-type biosorbents was reported in this work. two types of biosorbents containing a marine microalga, heterosigma akashiwo (hada) hada, or a purple non-sulfur bacterium, rhodobacter sphaeroides, were prepared. the micro-organisms inactivated by steam sterilization were immobilized in casein floc and cross-linked with glutaraldehyde. in the present immobilizing method, we obtained the biosorbents comprising as much as 67% of micro-organism on a dry-weight ...	2002	16290600
involvement of senc in assembly of cytochrome c oxidase in rhodobacter capsulatus.	senc, a sco1 homolog found in the purple photosynthetic bacteria, has been implicated in affecting photosynthesis and respiratory gene expression, as well as assembly of cytochrome c oxidase. in this study, we show that senc from rhodobacter capsulatus is involved in the assembly of a fully functional cbb(3)-type cytochrome c oxidase, as revealed by decreased cytochrome c oxidase activity in a senc mutant. we also show that a putative copper-binding site in senc is required for activity and that ...	2005	16291681
regulation of cellular caveolin-1 protein expression in murine macrophages by microbial products.	previously, we reported that expression of caveolin-1 in elicited peritoneal mouse macrophages was up-regulated by remarkably low (1.0-pg/ml) concentrations of escherichia coli o111 lipopolysaccharide (lps). here we report that increases in caveolin-1 expression are manifested by different types of lps, lps-mimetic taxol, and heat-killed e. coli and to a much lesser extent by zymosan, polysaccharide-peptidoglycan, and heat-killed staphylococcus aureus. rhodobacter sphaeroides lipid a (rsdpla) co ...	2005	16299308
the timing of proton migration in membrane-reconstituted cytochrome c oxidase.	in mitochondria and aerobic bacteria energy conservation involves electron transfer through a number of membrane-bound protein complexes to o2. the reduction of o2, accompanied by the uptake of substrate protons to form h2o, is catalyzed by cytochrome c oxidase (cco). this reaction is coupled to proton translocation (pumping) across the membrane such that each electron transfer to the catalytic site is linked to the uptake of two protons from one side and the release of one proton to the other s ...	2005	16306266
the assembly and organisation of photosynthetic membranes in rhodobacter sphaeroides.	recent afm data demonstrate that mature photosynthetic membranes of r. sphaeroides are composed of rows of dimeric rc-lh1-pufx complexes with some lh2 complexes 'sandwiched' between these rows of core complexes, and others in discrete lh2-only domains which might form the light-responsive complement of the lh2 antenna. the present work applies membrane fractionation, radiolabelling and lds-page techniques to investigate the response of r. sphaeroides to lowered light intensity. the kinetics unde ...	2005	16307117
ecophysiology and molecular phylogeny of bacteria isolated from alkaline two-phase olive mill wastes.	the use of two-phase centrifugal decanters has been widely adopted in the olive oil extraction industry in order to reduce the huge quantities of wastewaters produced during the traditional three-phase extraction process. the resulting sludge-like byproduct, widely known as "alpeorujo", has a ph of 4-6, low water activity (a(w)) and high phytotoxicity. addition of ca(oh)(2) to alpeorujo, which is commonly performed at the olive oil mill to handle disposal problems related to acidic ph and odor e ...	2006	16307869
aerobic anoxygenic photosynthesis genes and operons in uncultured bacteria in the delaware river.	photosynthesis genes and operons of aerobic anoxygenic photosynthetic (aap) bacteria have been examined in a variety of marine habitats, but genomic information about freshwater aap bacteria is lacking. the goal of this study was to examine photosynthesis genes of aap bacteria in the delaware river. in a fosmid library, we found two clones bearing photosynthesis gene clusters with unique gene content and organization. both clones contained 37 open reading frames, with most of those genes encodin ...	2005	16309388
putative novel photosynthetic reaction centre organizations in marine aerobic anoxygenic photosynthetic bacteria: insights from metagenomics and environmental genomics.	photosynthetic core complexes of anoxygenic bacteria consist of reaction centres (rcs) surrounded by light-harvesting complexes (lhc). the structural proteins of the rc-lhc1 complex are encoded by the puf-operon. we find diverse operon organizations of puf-operons that reflect structural differences of the core complex in marine aerobic anoxygenic photosynthetic bacteria (aanp). by analysis of environmental dna records coming from aanp bacteria we find several unknown proteins downstream to the ...	2005	16309398
structural and mutagenesis studies on the cytochrome c peroxidase from rhodobacter capsulatus provide new insights into structure-function relationships of bacterial di-heme peroxidases.	cytochrome c peroxidases (ccp) play a key role in cellular detoxification by catalyzing the reduction of hydrogen peroxide to water. the di-heme ccp from rhodobacter capsulatus is the fastest enzyme (1060 s(-1)), when tested with its physiological cytochrome c substrate, among all di-heme ccps characterized to date and has, therefore, been an attractive target to investigate structure-function relationships for this family of enzymes. here, we combine for the first time structural studies with s ...	2006	16314410
the solution structure of the appa bluf domain: insight into the mechanism of light-induced signaling.	the transcriptional antirepressor appa from the photosynthetic bacterium rhodobacter sphaeroides senses both the light climate and the intracellular redox state. under aerobic conditions in the dark, appa binds to and thereby blocks the function of ppsr, a transcriptional repressor. absorption of a blue photon dissociates appa from ppsr and allows the latter to repress photosynthesis gene expression. the n terminus of appa contains sequence homology to flavin-containing photoreceptors that belon ...	2006	16323221
my daily constitutional in martinsried.	the three-dimensional structures of bacterial reaction centers have served as the framework for much of our understanding of anoxygenic photosynthesis. a key step in the determination of the structure of the reaction center from rhodobacter sphaeroides was the use the molecular replacement technique. for this technique, we made use of two sets of data. first, x-ray diffraction data had been measured from crystals of the reaction center from r. sphaeroides by our research group in california, led ...	2004	16328817
regulation of photosystem synthesis in rhodobacter capsulatus.	control of the synthesis of the purple bacterial photosystem has been an active area of research for many decades. the period of the 1960s involved physiological characterization of photosystem synthesis under different growth conditions. in the 1970s barry marrs and coworkers developed genetic tools that were used to define and map genes needed for synthesis of photopigments. the 1980s was a period of cloning and physical mapping of photosynthesis genes onto the chromosome, the demonstration th ...	2004	16328832
rhodestrin: a novel indole terpenoid phytohormone from rhodobacter sphaeroides.	a new phytohormone was isolated as a metabolite of anthranilate photobiotransformation by rhodobacter sphaeroides ou5. it was identified by ms and nmr ((1)h, (13)c) as an indole terpenoid ester [(2e,4e,6e,8e,10e,12e,14e,16e,18e)24-hydroxy-2,6,10,14,19 pentamethyl tetrecosa-2,4,6,8,10,12,14,16,18 nonenyl-2(hydroxy methyl)-1h-indole-3-carboxylate] and is named as rhodestrin. rhodestrin at 50 nm: gave positive test in auxin bioassay and initiated more profuse and early rooting in tissue-cultured pl ...	2005	16328987
architecture of the native photosynthetic apparatus of phaeospirillum molischianum.	the ubiquity and importance of photosynthetic organisms in nature has made the molecular mechanisms of photosynthesis a widely studied subject at both structural and functional levels. a current challenge is to understand the supramolecular assembly of the proteins involved in photosynthesis in native membranes. we have used atomic force microscopy to study the architecture of the photosynthetic apparatus and analyze the structure of single molecules in chromatophores of phaeospirillum molischia ...	2005	16330228
time-resolved spectroscopic studies of the appa blue-light receptor bluf domain from rhodobacter sphaeroides.	appa is a blue-light and redox-responding regulator of photosynthesis gene expression in rhodobacter sphaeroides. detailed time-resolved fluorescence spectroscopy and subpicosecond transient absorption spectroscopy study of the bluf domain is presented for wild-type appa (appawt) and a photoinactive y21f mutant of appa. the main findings discussed here are that (1) time-resolved laser excitation studies on dark-adapted protein show that appawt and y21f mutant protein exhibits a fluorescence deca ...	2005	16331957
regulation and characterization of two nitroreductase genes, npra and nprb, of rhodobacter capsulatus.	among photosynthetic bacteria, strains b10 and e1f1 of rhodobacter capsulatus photoreduce 2,4-dinitrophenol (dnp), which is stoichiometrically converted into 2-amino-4-nitrophenol by a nitroreductase activity. the reduction of dnp is inhibited in vivo by ammonium, which probably acts at the level of the dnp transport system and/or physiological electron transport to the nitroreductase, since this enzyme is not inhibited by ammonium in vitro. using the complete genome sequence data for strain sb1 ...	2005	16332736
novel primers reveal wider diversity among marine aerobic anoxygenic phototrophs.	aerobic anoxygenic phototrophic bacteria (aanps) were previously proposed to account for up to 11% of marine bacterioplankton and to potentially have great ecological importance in the world's oceans. our data show that previously used primers based on the m subunit of anoxygenic photosynthetic reaction center genes (pufm) do not comprehensively identify the diversity of aanps in the ocean. we have designed and tested a new set of pufm-specific primers and revealed several new aanp variants in e ...	2005	16332899
substitution of isoleucine l177 by histidine affects the pigment composition and properties of the reaction center of the purple bacterium rhodobacter sphaeroides.	using site-directed mutagenesis, we obtained the mutant of the purple bacterium rhodobacter sphaeroides with ile to his substitution at position 177 in the l-subunit of the photosynthetic reaction center (rc). the mutant strain forms stable and photochemically active rc complexes. relative to the wild type rcs, the spectral and photochemical properties of the mutant rc differ significantly in the absorption regions corresponding to the primary donor p and the monomer bacteriochlorophyll (bchl) a ...	2005	16336186
effects of oxygen, heavy water, and glycerol on electron transfer in the acceptor part of rhodobacter sphaeroides reaction centers.	the kinetics of electron transfer between primary and secondary quinone acceptors of the photosynthetic reaction center (rc) of the purple bacterium rhodobacter sphaeroides wild type was studied at the wavelengths 400 and 450 nm. it was shown that removing of molecular oxygen from rc preparations slowed down the fast phase of the process from 4-4.5 microsec to tens of microseconds. similar effects were observed after the incubation of rc in heavy water for 72 h or glycerol addition (90% v/v) to ...	2005	16336188